bug#23653: 25.1.50; ‘<mouse-1>’ in gnus-article-buffer (and probably somewhere else) behaves wrong

[Dmitry Alexandrov]

Steps to reproduce:

‘M-x gnus’, open any article, press and release a first mouse button
(left on right-handed mouse, ‘<mouse-1>’) somewhere in article buffer
but not on any clickable element (link).

Actual result: selection is activated, point starts to follow mouse, as
if the button were pressed and not released.  I have to press ‘C-g’ or
something else to cancel it.

Expected result: point is positioned.

This bug seems to be introduced by this commit [0].

[0] 
http://git.savannah.gnu.org/cgit/emacs.git/commit/lisp/wid-edit.el?id=72166f2f3dba18f1217c666574032f5a0351ed65


GNU Emacs 25.1.50.1 (x86_64-unknown-linux-gnu)
Repository revision: 190942baeff3f541abf2a937e0fb4d3f9ea104be